NEW YORK — A judge declared a mistrial Tuesday after jurors said they could not reach a verdict in the case of a mental patient who slashed a New York City psychotherapist to death with a meat cleaver.
The defense didn’t dispute that David Tarloff killed Kathryn Faughey in February 2008, but defense lawyers said he was so psychotic that he couldn’t tell what he was doing was wrong.
The Manhattan district attorney’s office said Tarloff carried out a deliberate plan and understood it was illegal. It plans to retry the case.
Tarloff told authorities he set out to rob Faughey’s officemate, encountered her instead, and thought she was evil. Tarloff envisioned getting money from the holdup to whisk his sick mother away to Hawaii.
It was the jury’s 10th day of deliberations.
‘‘It’s very disappointing for us, but we will be back until we get justice in this case for our sister,’’ said Owen Faughey, one of the victim’s brothers.
‘‘We’ll do whatever it takes, and we will see justice, I’m sure of that,’’ said another, Michael Faughey.
Faughey, 56, specialized in helping people with relationships. She had never met Tarloff, let alone treated him.
‘‘We’re terribly disappointed that the jury could not reach a unanimous decision,’’ said defense lawyer Frederick Sosinsky.
‘‘We believe this was a very powerful case for a ‘not responsible’ verdict, as rare as those verdicts might be.’’